System for geometrically accurate compression and decompression

• US 7,027,658 B2
• Filed: 12/18/2001
• Issued: 04/11/2006
• Est. Priority Date: 12/20/2000
• Status: Expired due to Fees

• Current Assignee: Level Set Systems
• Original Assignee: Level Set Systems
• Inventors: Zhao, Hong-Kai, Osher, Stanley Joel
• Primary Examiner(s): Couso, Jose L.
• Application Number:
  US10/039,748
• Publication Number:
  US 20030025703A1
• Time in Patent Office: 1,575 Days
• Field of Search: 382232-236, 382238-240, 382242-243, 382/100, 382/284, 382/305, 348/113, 348117-119, 348121-123, 701/1, 701/13, 701/14, 342/25.R, 342/46, 342/52, 340953-957, 340967-970
• US Class Current: 382/243
• CPC Class Codes: G06T 9/004 Predictors, e.g. intraframe, interframe coding

Abstract

A system is disclosed providing accurate compression, storage, transmission and reconstruction of both simulated and empirical data representing terrain and other physical or hypothetical signals or surfaces, in one or multiple dimensions. In one embodiment, a gradient of an original surface is generated, and the data representing that gradient is compressed, then stored and/or transmitted. Reconstruction of the gradient yields an accurate representation of the original gradient. An alternative embodiment includes taking a second gradient of the original surface before compression, in which case reconstruction yields the second gradient, from which the first gradient can also be recovered.

Claims

1. A method for compressing and decompressing digital terrain elevation data, images, or graphs in at least two dimensions, including the steps of:

computing a numerical approximation to at least one of the slope, curvature, and/or another predetermined geometric feature, and storing the numerical approximation together with data values prescribed at certain predetermined locations;

applying a suitable compression technique to the geometric feature; and

retrieving the image;

wherein the retrieving step is carried out by numerically solving for the viscosity solution of the Eikonal Equation, using a source term derived from the compressed slope.

2. The method of claim 1, wherein the retrieving step is repeated N times, with N taken from the degree of the differential operator associated with the geometric feature.

3. The method of claim 1, wherein the viscosity solution is solved by adding the source term derived from the compressed slope to a source term derived from the error in the compressed slope.